Losing hair/scabs

My friends son brought home a kitten today that is covered in scabs and has clumps of hair missing.

Any ideas what this could be?

If it's mange, can that spread from the kitten to her to me to my cats? Or do the cats need direct contact?

I suggest that your friend and her son take the kitten to a vet asap to get it vaccinated for deadly diseases and wormed, get the skin checked, etc.  It is most likely a flea allergy and the vet might give it a cortisone shot to help heal from that  It could also be mites and/or fungus.  You will not catch mites (mange) from a cat but your cats could, and while the kitten may bring fleas into the house they are more likely to bite the cats than you.  If it is a fungus, it is possible for humans to catch that from a cat, and your other cats could also get it if their immune systems are not strong, and while not dangerous, it can be a nuisance to clear up.  The best thing for your friend to do is take the kitten to a vet right away and start on the road to recovery and health.